Warm-air furnace



D. M. MORPHY WARM AIR FURNAGE Dec. 29, 1925- A l Filed June 1e, 1923 VENT R Patented Dec. 29, 1925.

` UNITES STATES 1,561,287 PATENT OFFICE.

DAVID M. MORPHY, OF DE KALB, ILLINOIS, ASSIGNOR T U'IICA HEATER COMPANY, OF UTICA, NEW YORK, A CORPORATION OF NEW YORK.

WARM-AIR FURNACE.

Application filed .Tune 16, 1923.

To all whom t may concern:

Be it known that I, DAVID M. lNIonrHY, United States citizen, residing in De Kalb, Illinois, have invented the following described Improvements in farm-Air Furnaces.

The invention relates to air heating furnaces for dwellings and the like. Its principles are applicable to various types of air heating furnaces but are particularly suited for socalled return-flue-radiator heaters which are well known in the art, and the object is to admit supplemental air to the burning fire gases in such furnaces, in such way as toV improve the combustion etiiciency and therefore eliminate or reduce the production 0f smoke and so that .this result can beobtained not only occasionally or with one grade of coal, but continuously and with bituminous coals of any of the several varieties that are sold in different parts of the country and which, as well known, differ very considerably in their smoke-producing `propensities. The furnace design herein disclosed in illustration of the invention, is suited'for easy smokeless operation on any of these coals as well as with other fuels and is also adapted by its general method of organization for prolonged and practically in- 3) definite use without impairment, as by the burning out of the supplemental airadmis sion means or by unequal expansions and contractions and notwithstanding' that the said means is devoid of water-back protection heretofore found more or less indispensable in supplemental air furnaces.

In the drawings Fig. l is a' vertical central elevation of a warm air furnace with parts shown in central section.

Fig. 2 is a top plan of the heater proper.

Fig. 3 is a horizontal section, enlarged, of the air-admission ring of Fig. l.

Fig. t is a perspective thereof, and

Fig. 5 a perspective of a modified ring.

The furnace comprises a main enclosingl shell or outer casing l adapted for connection at the bottom with a source of fresh air and at the top with a number of hot air pipes leading to the rooms to be heated, as customary. In the ease of so-called pipeless furnaces the entrance for the aii to be heated and for the heated air is through a floor radiator connected to the top of the casingv as will be understood by those familiar with Serial No. 645,723.

this art, but in either case the design of the casing is of no consequence to this invention. It is commonly made of sheet iron supported and braced by suitable interior framing and is commonly and preferably provided with a cast metal front panel, 2, designed to accommodate the several entrances to the heater proper enclosed by it. The heater comprises a base or ash-pit section 3 provided with a conduit tunnel 4 extending to and preferably through the panel front where it is provided with a door through which ashes may be removed and also with a damper for the entrance of the main supply of combustionsupporting air. The two lire-pot sections 5 are mounted one above the other on the ashpit section and above the level of the grate 6, and the tire chamber dome 7 is mounted upon these sections and provided with a doorway or fuel feed conduit 8 extending horizontally to or through the casing frontwhere it is closed by the usual feed door. The dome 7 of the fire chamber tapers with a gradual taper, to a restricted outlet at its top which outlet is above the level of the fuel feed doorway. All of the fire gases pass through this restricted outlet into the radiator which constitutes the top of the heater. The connection between the lire chamber and the radiator of the heater is formed by an air-admission ring 9 which as herein shown 4is preferably a separately made part or structure fitted on its upper and lower sides to the bottom of the radiator and the top of the tire chamber, respectively, by means of a circular mortise and tenen joint such as is commonly used between heater parts, the grooves of these joints being relatively wide with respect to their tenon members so as to accommodate differences in the thermal expansions of each part with respect to the others. The air-admission ring S) is most simply made as a hollow, ring-form, onepiece casting having an inside diameter about equal to that of the restricted tire chamber outlet and an outside diameter somewhat larger than the outside diameter of said outlet. Its inner wall is provided with one or more holes, and its outer wall is provided with a bossed opening adapted to fit and support one end of a square air duct casting 10, the other end of which extends to the furnace front, directly over the `fuel feed conduit. and is supplied with a door or damper il. Under the pull of .the

chimney, air drawn directly from atmosphere through this duct and ring, supplemental to the air admitted through the ashpit, and is distributed by the ring into the fire gases issuing from the fire chamber, the condition and manner of' such distribution being such as to produce the new results above-stated and as will be later described.

The radiator is of common des-ign and responds to the condition that air heating furnaces must be low in height in order that the hot air pipes which lead from the top of the casing may have the necessary rise or upward slope.` Consequently itis composed of flues which are all arranged in a common level or horizontal plane and provided with a central, downwardly opening entrance part 12 which is herein vtermed the elbow of the radiator because this is the part which isr directly fitted to the air-admission ring and receives and turns, fire gases. from an upward into. an horizontal direction of movement. From this elbow, the fire gases divide and. flow reversely through the two semi-circular flues 13 to the single hre gas outlet 1e located yat-the rear. side. of the radiator,` but soT far as concerns thisl invention, the path or, shape of the flues of the radiator. is` quite. unin'iportant.v lt is only necessary that between the gas inlet or el-` bow 12 and the surrounding flue structure 13, there shall be present a ring-form airduct section exposed to contact with the current of partially heated air which flows upwardly along and over`V the surface of the lire dome?. rEllis current of air, together with the. air drawn in through the duct 10,

is relied on for keeping the. air-admission ring 9, which projects into said current, from acquiring yan injurious temperature. It will be understood that the edect of supplemental air-admission, when properly designed stimulates the combustion so as to generate a. most intensel and white-hot flame which is veryV apt to burn out the iron of the admission means unless precautions)7 are taken against it. It is neces,- sary however, that the admittedl air be well heated for mixture with the fire gases and the pnoblem of thus heating the air without endangering the iron has therefore been a difficult one.V By gradually'tapering the fire dome 7^ and making its upper, outlet part of about the same diameter as the` radiator elbow, the construction is adapted to permit the rising air to'flow freely and,A practically straight from the exterior of the fire chamber into the annular air passage through the radiator andfurther, by locating the outer wall of the air ring 9 so that it s exposed, to, or projects into, this unobstructed air current, an effective but entirely safe temperature condition is obtained, and irrespective ofV other features of this invention, this arrangement of the parte represents an advance in the art of aii heating furnaces of this type. lt is easily distinguished from prior efforts in the same direction wherein the air-admission ring or passage is either contained within the boundary` of the outlet part of the fire pot or located behind or between abrupt shoulders, or in the waist of the structure so to speak, so that the upward air current cannot easily reach and cool it, Jr else such rings have not been located at 'the most efficient point in the fire gas flown which is at the restrictedjunction between the fire chamber and the elbow partof the horizontal ring-form radiator as above pointed out.

A clean mt conduit 15 is formed on or connected to the radiator on its .front side, extending to or through the panel front and there provided with a clean-out doorf16. When the radiator is formed of a single casting, as` inl the present case, it is re inforced by a vertical web 17 between the free end of the elbow and the outlet side directly in line with the air-admission duct,

10 while the round holes 18 are evenly spaced around the opposite side. The ring thus has a greater cross area for the de. livery of air'into the lire gases on one side than on the other and the side of greatest' i area is located on the side toward which the fire cgases are turned by the elbow-12, This disposition of the air-admission entrance means, as shown by Figs. 8 and et, 'is preferable for the larger sizes of furnaces and prodntes the best mixing effect and the best combustion reslults. For smaller sizes, wherein forV example l the interiory diameter of the air-ad1nission ring' is not more than about six inches, the soleadmission for the air is through the single hole 19 without any air holes von the op.- posite side, but in either case it will be noted, the ring presents a greater cross area for air-admission on one side than on the other, and in both cases the side of maximum area is on the side toward wlnch the elbow 12 turns the gases, that is to say, toward the front of the furnace in ther form under description.

It is desirable, also, that the air duct 10 be located between the radiator, or the air to a correct temperature, but with respect to the essential principles of the invention it will now be clear that they may be incorporated in various different ways and shapes.

I claim l. In an air heating furnace, the combination of a radiator comprising a horizontal ring-form ilue having a downwardly opening gas inlet elbow at the center and an upward air passage between said flue and elbow, a .fire chamber having a fuel feed conduit and a restricted gas outlet above the level of said conduit and of substantially the same diameter as said elbow, a separately made, air-conducting ring interposed between and connecting the fire chamber outlet with said elbow inlet, an air supply duct open to atmosphere for admitting supplemental air to said ring and exit means in the ring for delivering such air into the fire-gas flow in the ring connection.

2. In an air heating furnace, the combination of an enclosing outer casing having a panel front, a radiator therein comprising a horizontal ring-forni flue having a gas outlet at one side, a downwardly open gas inlet elbow at its center and a space between saidflue and elbow forming an upward air passage, a fire chamber within the casing having a restricted gas outlet at its top and a fuel feed conduit extending laterally therefrom at a lower level and connected to said panel front, a separately made, airadmission ring interposed between and connecting said restricted gas outlet to said radiator inlet and having an air supply duct extending laterally therefrom to said panel front directly over said feed conduit, said duct and ring serving to heat and conduct supplemental air from the atmosphere and deliver it to the fire gases flowing from the fire chamber to the radiator.

3. In an air heating furnace, the combination of a casing, a radiator therein comprising a horizontal, ring-form flue having a downwardly opening gas inlet elbow at the center and an annular air passage between said iiue and elbow, a fire chamber having an upwardly tapered dome terminating` in a restricted gas outlet of substantially the same diameter as said elbow and a separately made, hollow, air-admission ring forming the connection between said gas outlet and said elbow inlet and of greater external diameter than either of them, said several parts being mutually organized and related t0 permit the upward air current rising around the fire chamber to flow freely along said tapered dome and in cooling contact with the exterior of said hollow ring, and thence directly upwards through the air passage around said radiator elbow.

4. In an air heating furnace, the combination of an enclosing casing having' a front,

a radiator therein comprising a horizontal ring-form flue having a downwardly open gas inlet elbow at its center and an annular space between said flue and elbow forming an upward air passage, a fire cham ber within the casing having a tapered dome with a restricted gas outlet at its top vof substantially the same diameter as said elbow and a fuel feed conduit extending laterally from said chamber, at a lower level to the furnace front, a separately made hollow, airdelivering ring connecting said restricted gas outlet to said radiator elbow and having an air supply duct extending laterally therefrom and connected with said front, the outer wall of said ring being disposed projecting into the air current upwardly flowing over said dome and around said radiator elbow.

5. In a furnace, the combination of a itor comprising a horizontal ring-form eras flue having a central inlet elbow in the same plane as the flue and forming an annular air passage through the radiator, a fire chamber having a laterally extending fuel feed conduit and an upwardly tapered and restricted gas outlet connected to said elbow inlet above the level of said conduit supplemental air-admission means located at the connection of said parts and comprising an annular air passage having its outer wall vertically above thewall of the fire chamber and vertically below said annular radiator air passage and adapted to intercept the rising air current from said chamber through said annular passage.

6. In a furnace, the combination of an outer casing having a front, a radiator therein comprising a horizontal ring-form flue having a lateral cleaning-out entrance connected to an opening in said front and a central gas inlet elbow, said entrance lllue and elbow all occupying a common horizontal plane and providing an upward air passage between the flue and elbow, a lire chainber having a restricted gas outlet at its top and a fuel feed conduit connected to said front, a separately made air-delivering ring interposed between and connecting said elbow inlet with the lire chai'nber outlet, and an air supply duct connecting said ring to an opening in the casing front and located beneath said cleaning-out entrance and above said fuel feed conduit.

In a furnace, the combination of a lire chamber having a main air entrance and an upward fire-gas outlet, a gas-conducting airheating radiator connected to and above said outlet and supplenu-mtal air-admission means at the junction of said parts having a greater area. for the delivery of air on one side of the gas flow than on the other.

S. In a furnace, the combination of a iire chamber having an upward fire-gas outletJ a return-flue radiator having a central gas inlet part connected to said outlet and of substantially the same diameter as said outletand air-admission means surroundingv the junction of said parts having a greater air-delivering efficiency on one side of said junction than on the other, and disposed for contact with the upward air current from the tire chamber through theV radiator.

9.4 In a furnace, the combination of a fire chamber having a main air entrance and a dome with a restricted lire-gas outlet at its top, a gas-conducting, air-heating radiator connectedl to said outlet andmeans for admitting supplemental air to the gas flow to the radiator having a greater area for delivery of said air on one side of the gas flow than on the other.

10. In a furnace, the combination of a f fire chamber having a gas outlet, a gas-conducting radiator having an inlet elbow connected with said outlet and means for admitting supplemental. air in the region of the junction of said parts having its greatest air-delivery area on the side toward which the elbow turns the gases in the radiator.

l1.v In a furnace, the combinationof a fire chamber having a fuel feed: doorway and a gas outlet, a gas-conducting radiator having an inlet elbow connected with said outlet and means for admitting'. supple-1` mental air in the region of the junction of said parts having its greatest airsdelivery area on the` side adj acent said fuel doorway.

12. In a furnace, the'combination of an.'

air-heating radiator comprising a horizontal ring-form fine having a central inlet elbow, the spacebetween said flue and elbow forming Ian'airv passage, a fire chamber having a restricted gas outlet of substantially the same diameter as said elbow and an air-admission means at the junction of the fire chamber and elbow having a greater airdelivery area on one side than on the other.

13. In a furnace, the combination of an air-heating radiator comprising a ring-form flue having a central inlet elbow, the space between said? flue'and elbow forming an'upward air passage, a fire chamber having a restricted gas. outletv of about the samer di ameter as said elbow, a separately made hollow, ring-form member constituting an admission means for supplemental air interposed between and supporting the radiator onjthe fire chamber, and connecting said outlet to the elbow inlet, the inner wall of said member being provided with air exit means on the side thereof 'towards which the elbow turns the fire gases.

111-. In a furnace, the combination of a radiator comprising a central inlet elbow and providing an upward air passage around the same, a fire chamber having a restricted gas outlet communicating with said elbow inlet, means for admitting supplemental air to said communication having greatest air-delivery area on the elbow side and an air supply duct connected to said member also on the elbow side.

l5. In a furnace, the combination of a radiator comprising a horizontal, air-heating, ring-form Hue having an inlet elbow at its center, both in substantially the same horizontal plane, the space between said fine and elbow forming an upward air passage, a fire chamber having a restricted gas outlet communicating with said inlet, a member for admitting supplemental air to said communication having greater air-delivery area on the side of the elbow connecvtion to the ring-form flue than elsewhere, an air supply duet connected to said member on the side of maximum deliveryqarea and a fuel feed conduit for the lire chamber situated at av lower level than said air duet.

16. In a furnace, the combi-nation of a radiator comprising a horizontal ring-form fine liaving a central! inlet elbow i-n the same pla-ne as. the flue and forming an upward air' passage through the radiator, a fire chamber having a laterally extending fuel feed conduit and a restricted gas outlet connected tol said elbowl inlet above the level of said conduit, supplemental air-admission means in the region of said connection having more efficient air-delivery means adjacent the elbow connection` to said iue than elsewhere and an air suppl-y duct for sa'id mea-ns connected toY atmosphere.

117i.. In an heating furnace, the combination of 'a radiator having a gas inlet,v a fire chamber'having a restricted-gas outlet supporting said radiator and connected to thev inlet4 thereof, an annular air passage surroundingfthegasesf'li'owing from the chamber tothe radiator, an air supply duct leading to said' annular passage and a single delivery opening from said passage into the fire gas flow. f

In testimony whereof, I' have signed this specification.

DAVID M. MOR-PHY. 

